The launch date was set in stone. 12 June; World Day Against Child Labour; opening day of the football World Cup. With just months to go, we were looking for a big idea that would enable us to harness the power of communications to reach traditional and new audiences with a strong message about the 168 million children in child labour.

We had not planned on using that most ancient way of expression – music – but through our artists’ engagement programme, Artworks, we learnt that a US musician, Mike Einziger, was interested in the ILO’s work and wanted to contribute. He is the Grammy-nominated lead guitarist for the rock band, Incubus, who wrote the guitar riff for one of the biggest pop songs of 2013, Wake Me Up. We set up a meeting and he told us he wanted to write us a song about child labour. Download the song | Learn about the campaign

My colleagues and I knew immediately that the combination of ILO expertise, social media and the pull of a well-known artist could work. Given that he’s a top musician with a punishing schedule, our first worry was whether he would be able to deliver. But he did just that, taking part in teleconferences, asking for information about child labour, sending us emails and video messages. Within weeks, he and violinist Ann Marie Simpson had written the lyrics to ‘Til Everyone Can See and had recorded a demo tape.

Mike Einziger, Hans Zimmer, Ann Marie Simpson and Dominic Lewis film the music video for the song ‘Til Everyone Can See. Download the song

The gentle style was not what we had expected from a rock guitarist but there was something almost mesmerising about the rhythm and the lyrics that drew us in. Einziger was so enthusiastic about the project that he spoke with several of his musician friends, including Oscar-winning film composer, Hans Zimmer, and Grammy Award- winning singer and producer, Pharrell Williams, who also wanted to take part.

We planned to do a music video along with the song, so that we could promote it online and on social media, as a way of getting people to sign-up to take action against child labour. With a tight deadline, Pharrell on tour, and other participating artists in different locations, the producers in Los Angeles had to record several of the musicians remotely and mix the sounds and visuals in the studio.

Williams, who has achieved global fame for his song Happy, stopped off in London on his way back from Japan, to record the song. The drummer, Travis Barker, from the group Blink-182, also recorded remotely. Composer, Dominic Lewis, singer LIZ and anti-child trafficking activist Minh Dang, also took part. All of these artists gave their time and skills for free, as their contribution to the fight against child labour.

With the guidance of the ILO’s technical experts, we integrated film of child labour into the music video, along with the campaign’s messages and branding.

The song and video became the centrepiece of our online strategy, which was designed to encourage as many people as possible to support the campaign and the work of the ILO. Using traditional media, internet and social media, key messages on child labour were multiplied, shared and duplicated.

To date, audiences from more than 105 countries have listened to the song on the site; more than 35,000 people have viewed the video on YouTube; On Facebook, posts relating to the campaign have appeared in the newsfeeds of over 1 million users. The figures are going up all the time.

We want to keep the momentum going, so please join the campaign and download the song to get updates on how you can help combat child labour.